1. Field of Invention
This invention relates to the handling and storage of attributes in a print management system. In particular, this invention is directed to the separate storage of persistent and non-persistent attributes.
2. Description of Related Art
Print management systems provide a method to control and access various printers and to manage other related information remotely. However, in the current systems, the extent to which these functions can be utilized is limited by the fixed set of predefined system attributes.
Attributes are collections of data that describe the entities that compose the print management system. In other words, attributes define or characterize print management systems abstract entities, or objects. For example, document attributes, such as plex, margin, orientation, etc., describe how the printed material should appear. Printer attributes, such as media-ready, fonts-ready, etc., describe the available resources or features of the printer. Other printer attributes may describe the various printing features that users may use to produce high-quality documents, or they may describe status or configuration information, such as the printer's state or location. In addition to these attributes, there are a set of attributes to facilitate end-user, operator and administrator functions. In summary, attributes are a set of data that describes the objects of the printer management system.
There are three basic elements to an attribute: an object identifier (OID), a syntax and a value. An OID is a globally unique identifier of an attribute which is coded such that it may be understood by all printing systems. The OIDs are allocated following a tree format, such that each printer vendor or standard organization is designed as a branch of this tree. Then each organization may assign unique OIDs by further branching out.
For example, the OID of "job-owner" is 1.0.10175.1.3.1.3 in the ISO 10175 standard for Document Printing Applications (DPA). If the server receives the "job-owner" attribute, the server can store the attribute or send this information to an account log upon completion of a print job using the OIDs, for example. Then, an accounting program written by a third party vendor can easily interpret the information in the accounting log through the OIDs.
The syntax of an attribute is the format in which the attribute value is represented. For example, the syntax of the "job-owner" attribute is "distinguishedNameString", which is an example of coded language the computer or printing system understands.
The value of an attribute is the instance of the attribute. For example, the value of "job-owner" could be "John Jones" , i.e., the name of the person to whom the print job belongs.
FIG. 1 is a diagram of a print management system 100 showing the interaction between the client 130, the server 110 and the output device 140. The output device 140 is, for example, a printer. The client 130 is the interface between the user and the print management system. The server 110 takes print requests from multiple clients 130, schedules print jobs based on the print requests and then forwards the print jobs to the output device 140.
For example, when a user submits a print job by selecting documents, the printer and other attributes, the client 130 puts together this data and sends it to the server 110. The server 110 then reads the data and stores the document data in a print data memory and creates an abstract entity, a job object, that contains the attributes specified in the data package from the client 130 and stores it in the object database 120. When the output device 140 is ready to print a new job, the server 110 retrieves the document data from the print data memory and sends the document data to the output device 140. The server 110 also retrieves the job object attributes from the object database 120, and based on these attributes, sends print controls to the output device 140.
The processing of attributes in a print management system is described, for example, in U.S. patent application Ser. No. 08/976,180, "FILTER INTERFACE FOR MANAGING PRINTER SYSTEM INFORMATION," filed Nov. 21, 1997, now U.S. Pat. No. 617,839 and U.S. patent application Ser. No. 08/966,406, "DYNAMIC EXTENSION OF PRINT CAPABILITIES," filed Nov. 7, 1997, now U.S. Pat. No. 6,055,063 the subject matter of which are incorporated herein by reference.
Many object-based programs store attributes persistently (i.e., stored in a resident memory and continuously read and updated), so that this information can be maintained during system restart. As shown in FIG. 2, an object database 120 is often used to achieve this persistency.
However, there are many attributes that do not need to be stored persistently, such as those that are reset at restart or are dynamically calculated. The storage of these non-persistent attributes in the object database increases the number of input and output transactions required, increases the use of disk space, and slows down system performance.